Math Puzzle – Sum of multiples 757 Views October 11, 2011 3 Comments Brain Teasers, Mathematics Rishabh Dev If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. Tagged math puzzle About author Rishabh Dev View all posts Rishabh Dev is the Founder, Author & Editor at Durofy.com. Start a conversation with Rishabh at email@example.com to know more.